geography_as_gml()

Datum geography_as_gml

(

PG_FUNCTION_ARGS

)

Definition at line 210 of file geography_inout.c.

{
        LWGEOM *lwgeom = NULL;
        GSERIALIZED *g = NULL;
        char *gml;
        text *result;
        int version;
        char *srs;
        int srid = SRID_DEFAULT;
        int precision = DBL_DIG;
        int option = 0;
        int lwopts = LW_GML_IS_DIMS;
        static const char *default_prefix = "gml:";
        const char *prefix = default_prefix;
        char *prefix_buf = "";
        text *prefix_text, *id_text = NULL;
        const char *id=NULL;
        char *id_buf;
 
 
        /* Get the version */
        version = PG_GETARG_INT32(0);
        if ( version != 2 && version != 3 )
        {
                elog(ERROR, "Only GML 2 and GML 3 are supported");
                PG_RETURN_NULL();
        }
 
        /* Get the geography */
        if ( PG_ARGISNULL(1) ) PG_RETURN_NULL();
        g = PG_GETARG_GSERIALIZED_P(1);
 
        /* Convert to lwgeom so we can run the old functions */
        lwgeom = lwgeom_from_gserialized(g);
 
        /* Retrieve precision if any (default is max) */
        if (PG_NARGS() >2 && !PG_ARGISNULL(2))
        {
                precision = PG_GETARG_INT32(2);
                /* TODO: leave this to liblwgeom */
                if ( precision > DBL_DIG )
                        precision = DBL_DIG;
                else if ( precision < 0 ) precision = 0;
        }
 
        /* retrieve option */
        if (PG_NARGS() >3 && !PG_ARGISNULL(3))
                option = PG_GETARG_INT32(3);
 
 
        /* retrieve prefix */
        if (PG_NARGS() >4 && !PG_ARGISNULL(4))
        {
                prefix_text = PG_GETARG_TEXT_P(4);
                if ( VARSIZE(prefix_text)-VARHDRSZ == 0 )
                {
                        prefix = "";
                }
                else
                {
                        /* +2 is one for the ':' and one for term null */
                        prefix_buf = palloc(VARSIZE(prefix_text)-VARHDRSZ+2);
                        memcpy(prefix_buf, VARDATA(prefix_text),
                               VARSIZE(prefix_text)-VARHDRSZ);
                        /* add colon and null terminate */
                        prefix_buf[VARSIZE(prefix_text)-VARHDRSZ] = ':';
                        prefix_buf[VARSIZE(prefix_text)-VARHDRSZ+1] = '\0';
                        prefix = prefix_buf;
                }
        }
 
        /* retrieve id */
        if (PG_NARGS() >5 && !PG_ARGISNULL(5))
        {
                id_text = PG_GETARG_TEXT_P(5);
                if ( VARSIZE(id_text)-VARHDRSZ == 0 )
                {
                        id = "";
                }
                else
                {
                        id_buf = palloc(VARSIZE(id_text)-VARHDRSZ+1);
                        memcpy(id_buf, VARDATA(id_text), VARSIZE(id_text)-VARHDRSZ);
                        prefix_buf[VARSIZE(id_text)-VARHDRSZ+1] = '\0';
                        id = id_buf;
                }
        }
 
        if (option & 1)
                srs = getSRSbySRID(fcinfo, srid, false);
        else
                srs = getSRSbySRID(fcinfo, srid, true);
        if (!srs)
        {
                elog(ERROR, "SRID %d unknown in spatial_ref_sys table", SRID_DEFAULT);
                PG_RETURN_NULL();
        }
 
        /* Revert lat/lon only with long SRS */
        if (option & 1) lwopts |= LW_GML_IS_DEGREE;
        if (option & 2) lwopts &= ~LW_GML_IS_DIMS;
        if (option & 8)
        {
                elog(ERROR,
                     "Options %d passed to ST_AsGML(geography) sets "
                     "unsupported value 8",
                     option);
                PG_RETURN_NULL();
        }
        if ((option & 4) || (option & 16) || (option & 32))
        {
                elog(ERROR,
                     "Options %d passed to ST_AsGML(geography) but are only "
                     "applicable to ST_AsGML(geometry)",
                     option);
                PG_RETURN_NULL();
        }
 
        if (version == 2)
                gml = lwgeom_to_gml2(lwgeom, srs, precision, prefix);
        else
                gml = lwgeom_to_gml3(lwgeom, srs, precision, lwopts, prefix, id);
 
    lwgeom_free(lwgeom);
        PG_FREE_IF_COPY(g, 1);
 
        /* Return null on null */
        if ( ! gml )
                PG_RETURN_NULL();
 
        /* Turn string result into text for return */
        result = cstring_to_text(gml);
        lwfree(gml);
 
        PG_RETURN_TEXT_P(result);
}

References getSRSbySRID(), LW_GML_IS_DEGREE, LW_GML_IS_DIMS, lwfree(), lwgeom_free(), lwgeom_from_gserialized(), lwgeom_to_gml2(), lwgeom_to_gml3(), precision, and SRID_DEFAULT.

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